FY 2026-27 GST filing calendar for builders — every due date, in one place

Nobody starts a construction business because they love GST returns. But miss a GSTR-3B due date and the late fee plus interest turns up on exactly the month your cash is tightest — the month you paid for steel, labour and the JCB in the same week. This is the FY 2026-27 filing calendar for builders and contractors, in plain language, with every recurring due date in one place.

The GST filing calendar for builders — the returns that actually apply to you

Most construction SMBs are on the regular scheme, so three filings matter month to month. A few small sub-contractors are on the composition scheme instead. Here is the short list:

• GSTR-1 — your outward supplies (the RA bills and invoices you raised). Monthly filers: typically due the 11th of the next month. QRMP (quarterly) filers: the 13th of the month after the quarter.
• GSTR-3B — the summary return where you actually pay tax after claiming input credit. Monthly filers: typically due the 20th. QRMP filers pay tax monthly via PMT-06 (25th) and file 3B quarterly (22nd or 24th, depending on your state group).
• CMP-08 — for composition-scheme dealers, a quarterly statement-cum-challan, typically due the 18th of the month after the quarter, with the annual GSTR-4 due later.
• GSTR-9 / 9C — the annual return and reconciliation, generally due 31 Decemberfollowing the financial year (so FY 2025-26's annual return falls in December 2026).

Dates get extended by CBIC notification more often than anyone would like, so treat these as the standing rule and check the portal near month-end. As of the last change, the 11th / 20th rhythm for monthly filers has held steady.

QRMP: the scheme most small contractors should be on

If your aggregate turnover is up to ₹5 crore, the Quarterly Return Monthly Payment scheme lets you file GSTR-1 and 3B once a quarter while paying tax monthly through a simple challan. Four filings a year instead of twelve. For a contractor doing three or four projects, that is a real reduction in the “oh no, it's the 19th” panic — as long as you still remember the monthly PMT-06 payment.

The late fee is small. The interest at 18% per annum on the tax you owed, running from the due date until you actually pay, is the part that bites.

The two things that actually make you miss a deadline

It is almost never that you forgot the date. It is one of these two:

• Your sales register isn't ready.RA bills are scattered across WhatsApp, a diary and three Excel sheets, so on the 19th you're still reconstructing what you billed. If your invoices are raised in one system, GSTR-1 is a report, not an archaeology dig.
• Input credit doesn't match GSTR-2B.A vendor didn't upload their invoice, so the credit you were counting on isn't there, and now 3B doesn't tie out.

Rebaar raises GST-compliant invoices (with e-invoicing / IRN where you cross the turnover threshold), keeps every RA bill in one ledger, and gives you a clean outward-supplies report so the 11th and the 20th become print jobs instead of all-nighters.

A simple month-end routine

Pin this to the wall: by the 5th confirm all last-month invoices are entered; by the 10th reconcile input credit against GSTR-2B; file GSTR-1 by the 11th; pay and file GSTR-3B by the 20th. Do that four months running and it stops feeling like a fire drill.

Want your RA bills, invoices and GST filing to live in one place so the calendar stops owning your month-end? Start free → or see how invoicing and compliance fit together.